Sunday, September 30, 2012

Junonia coenia, the common buckeye butterfly, is chestnut brown. The forewing has two orange bars and two bull's-eye spots; a white band surrounds the larger spot. The hindwing also has two spots; the upper one contains a purple crescent. Click to enlarge.

Buckeye caterpillars come in various forms but usually have an orange head, a black body with white and orange side stripes, and spiky blue spines along the top. More spines grow from orange bumps along the sides. Click to enlarge.

The buckeye is common throughout most of the United States, living year-round in the southern states. Every year when weather warms in late spring and early summer some buckeyes go north to colonize areas as far as southern Canada. Northern populations move southward in autumn, sometimes migrating in large numbers. Adults and caterpillars overwinter in the southern parts of the range.

Buckeyes are found in fields of flowers, open ares, roadsides, gardens, and parks. I saw dozens of adults and caterpillars this weekend while walking in the Edwin B. Forsythe National Wildlife Refuge on the New Jersey coast near Atlantic City.

Sunday, September 16, 2012

If you take a close look at a milkweed plant today you will probably see crowds of yellow oleander aphids on the stems. Before long a monarch butterfly will come for a drink of flower nectar. Turn over a leaf and you'll see milkweed bugs.

Milkweed bugs, Oncopeltus fasciatus, suck juices from milkweed tissues and seeds; they have piercing, sucking mouthparts that are like sharp straws. These three are warming up on a metal fence railing in a milkweed patch. The little one is an immature stage called a nymph. The other two are adults.

Milkweed bugs are bright red for a reason; it's a warning to anyone who might be thinking about eating one. Like monarch butterflies, milkweed bugs become poisonous from eating milkweed. A bird that eats a milkweed bug and gets sick will remember the bright colors and avoid them in the future. The strategy is called aposematic coloration.

Even among bright red bugs this one stands out. It has just molted its skin; the remnants are still attached to its tail end. Newly emerged insects are lighter-colored than usual and somewhat soft.

Milkweed bugs have seven stages: the egg, five increasingly larger immature stages called nymphs, and the adult. They don't make cocoons. Each nymphal stage looks a little different, but none of them have wings and they can't reproduce. Like other insects the milkweed bugs have exoskeletons that make them rigid on the outside. After growing as large as the skin will allow, they shed it and come out bigger. At this time of year and you will probably easily find all the nymphal stages and lots of adults on any milkweed plant. Click here to go to a site that has a nice drawing of the stages.

The newly emerged bug will soon darken, harden, lose that bit of old skin, and then get back to the business of eating milkweed. Mmmm... milkweed! Click on the photo to enlarge.

Sunday, September 9, 2012

Pink-spotted ladybugs are native to North America. They're common, but I don't see them very often; maybe they are good at hiding. This one was under a leaf.

They are flatter than most species of ladybugs and more elongated. They come in colors from pink to red. They have six spots on each wing cover, but two of those six are half circles mirrored on the other wing, so that when the wings close there seem to be ten spots on them. They have two black patches on the thorax (between the head and wings). Together, wing spots and thorax patches account for their other common name, the 12-spotted ladybug.

Look for them on plants where they forage for aphids, mites, and insect eggs. Unlike most ladybugs, they like to snack on pollen, and they are reported to be especially fond of dandelions.

About Me

I am a Collection Manager at the American Museum of Natural History in New York City. I live in Brooklyn. Most mornings I walk a few blocks to the subway station. I get off the train at 59th street in Manhattan and walk a mile along Central Park West through one of the most urban settings in the world. I see a nonhuman mammal or two, a few dozen birds, and a variety of intriguing insects every day; this blog is a collection of stories about them.
UPDATE, JUNE 2018: I retired from the museum and moved away from New York City. I'm in a little town on the Delaware across from Philadelphia that is teeming with urban and suburban wildlife. Best of all, I'm close to the New Jersey Pine Barrens which is unique and lovely and full of future blogs.

Here is a link to my book's webpage.

Urban Wildlife Guide

Blog Photos

The photos in this blog can be enlarged by clicking on them. I took all of them. If you want to use one, please ask permission in the comments section below the blog and I'll respond and let you know how to attribute. Thanks for reading!